The effects of light on the growth of plants have been studied over the years. Several studies have shown that by manipulating the wavelengths and duration of light directed at a selection of plant, their growth can be enhanced or reduced. Tissue culture, used widely in plant science, is the growth of plant tissues or cells within a controlled environment. Traditionally, tissue culture researchers' and horticultural industries have used artificial light sources for production. These light sources include, for example, high-pressure sodium lamp (HPS), metal halide lamp (MHL), incandescent lamp, etc. However, the abovementioned light sources are energy intensive, which means the power outputs of some of these lamps range from about 400 W to 1100 W. In commercial indoor horticultural applications, several of these lamps may be required to direct light over a large area. The power requirements and the costs incurred for conventional light sources are thus high. With energy being a point of concern for most commercial entities, a light source, which provides the necessary light with minimal power and cost requirements, is required.
Furthermore, photoreceptors, which are complex light-sensing systems within plants, respond to energy packets carried at specific wavelength signals measured in nanometers. These complex systems can convert light energy into kinetic energy. Phytochromes, cryptochromes, and phototropins are three well-defined photoreceptors. The arriving light energy signal induces chemical excitation and the transformation leads to the beginning of the process of photosynthesis. Wavelengths or wavebands ranging from about 600 nm to about 700 nm are particularly efficient for inducing verifiable changes in phytochromes, consequently modifying their photochemical kinetics, nuclear/cytoplasmic partitioning, ability to phosphorylate substrates, and physical interactions with downstream components for photomorphogenesis. Cryptochromes are active within the ranges of about 300 nm to about 500 nm wavelength bands and most notably between the 465 nm and 485 nm wavelength band. The photomorphogenesis effect activates the cycle within the photoreceptors thus propagating the life cycle. Additionally, the wavelength bands ranging from about 550 nm to about 580 nm have little or no effect on photosynthetic activity of plants. Existing light sources direct light from all wavelength bands without providing options for selectively supplying only wavelengths, which enhance and allow for manipulation within the life cycles of plants. A light source, which is capable of selectively supplying wavelengths of light that enhance the growth of all higher plant life, is required.
Hence, there is a long felt but unresolved need for a light emitting apparatus, which provides the necessary power spectral density (PSD) of Photosynthetic Active Radiation (PAR) while achieving sub-minimal power requirements to operate. Furthermore, there is a need for a light emitting apparatus, which is capable of selectively supplying wavelengths of light that not only enhance growth of plant life but is also used to manipulate all stages of plant life development with minimal power requirements to operate.